The present invention relates to the field of ultrasound imaging and, in particular, to the utilisation of ultrasound data for producing volume flow information.
In recent years, ultrasound imaging has become increasingly important, especially in the area of medical imaging of the internal portions of a person or animal""s anatomy. The principles of ultrasound imaging are well known. However, recently the utilisation of phase data from an ultrasound signal has resulted in the production of flow information associated with an ultrasound scan. A number of manufacturers now offer xe2x80x9cColour Doppler Imagingxe2x80x9d which provides information in the form of colour indicators showing the direction and speed of flow of blood within vessels.
It would be desirable to provide for non-invasive real time ultrasonic measurement of the blood volume flow rate in blood vessels with a high accuracy and high degree of robustness ideally utilizing standard hardware available with only software modification.
It is an object of the present invention to provide for the accurate measurement of flow volume within the vessels utilising ultrasound techniques.
In accordance with a first aspect of the present invention, there is provided a method of estimating the volume flow in a vessel utilising ultrasound techniques, the method comprising the steps of imaging the vessel utilising an ultrasonic transducer array so as to produce fluid velocity information for the vessel, the plane formed by the beams emitted by the transducers having a direction which is offset from the axis of the vessel such that the it forms an elliptical section within the vessel; and utilising the velocity information for points within the vessel and the elliptical section to calculate a mean velocity for the fluid flow through the elliptical section.
Preferably, the mean velocity is calculated using a power weighted average of the velocity information, the power weighting being correlated to the intensity of the received signal at each point corresponding to the velocity information.
Preferably, the method further comprises the step of fitting an elliptical section to the fluid velocity information and determining the elliptical section parameters for the vessel from the fitted elliptical section.
The method is ideally suited to use on the internal portion of a human or animal""s anatomy and can be implemented on a standard ultrasound machine by reprogramming of the software of the machine.